Heretofore, difficulties have been encountered in in-line feeding of cartridges into the receiver inlets of firearms, particularily of the bolt actuated blowback type, and in positive positioning of the cartridge in the receiver preparatory to in-line introduction thereof into the firing chamber by the bolt carrier. These difficulties were further compounded by the fact that the bolt, in moving to the in battery position to move the cartridge into the firing chamber from the receiver, was not positively controlled in its travel to assure a linear axial movement of the bolt. Thus if the cartridge was not axially aligned with the firing chamber while in the receiver and the traveling bolt was not axially aligned with the firing chamber, a misfire or jamming of the cartridge could occur as a result of improper feed and possible resulting stubbing caused by misalignments.
Furthermore, inherent in completion of the bolt travel to the in battery position is the uncontrolled bounce characteristics of the bolt on impact of the bolt with the receiver or barrel in chambering the cartridge in the firing chamber. Bounce has been recognized as a primary cause of out of battery firing of cartridges, i.e., premature firing or delayed ignition of the cartridge leading to firing out of battery.
Magazines have for years involved in their design complicated configuration requirements for containing rounds and also means to guide, pilot, and ramp rounds into the firing chamber in other than in-line feed.